There's an interview over at The Quietus with Jennifer Herrema, which includes this exchange:

Q: And you’ve written a track for the new Avalanches record?

A: Yeah, the 'Stepkids' one. Their dude at Modular the record label got in touch and said that Robbie wanted a song and sent the music and wanted a song about a lost kid, like a street kid, just something melancholy or whatever and thought that I’d be good at doing that and it turned out to be really easy. Actually Kurt and I did it together and then I sang it and sent it back over to them. Actually Robbie he wrote me last week and they’re gonna do a remix for this album and he updated me. He said that their album was gonna be done in three weeks and then he was gonna work on the Black Bananas remix. He told me the 'Stepkids' song he’d gotten some strings in there and he said it sounded awesome and I haven’t heard it but…

Notice the quote: "Robbie he wrote me last week .... He said that their album was gonna be done in three weeks..." We've all grown a bit skeptical of such statements, but it's interesting nevertheless.